Copley is best known for his work with director Neill Blomkamp in the films "District 9" and "Elysium." He played Stefan in this year's "Maleficent," and appeared as Murdock in 2010's big-screen "The A-Team." Forbes has a long history on TV, ranging from noted sci-fi series like "Star Trek: The Next Generation" and "Battlestar Galactica," plus a recent Emmy-nominated supporting performance on "The Killing."

Along with Deena Pilgrim (Susan Heyward on the "Powers" TV series), Christian Walker is the focus character of "Powers," a detective investigating super-powered related homicides -- and himself a former superhero. In the original "Powers" pilot produced for FX in 2011, the role was played by Jason Patric.

Retro Girl is a pivotal character in the first arc of the "Powers" comic book by Brian Michael Bendis and Michael Avon Oeming, a story titled "Who Killed Retro Girl?" Carly Foulkes played the character in the earlier pilot.

Copley and Forbes join a cast that already includes Heyward, along with Adam Godley as Captain Cross, Max Fowler as Krispin Stockley, Eddie Izzard as Wolfe, Noah Taylor as Johnny Royalle and Olesya Rulin as Calista. Based on the creator-owned comic by Bendis and Oeming (currently published by Marvel's Icon line, originally by Image Comics), "Powers" is set to debut on Sony's streaming PlayStation Network in December 2014.